Bomb fuse device



May 6, 1947 P. H. GIROUARD BOMB FUSE DEVICE Filed Feb. 3, 193s 2Sheets-Sheet' 1 May 6, 1947. P. H. GIROUARD Filed Feb. 3, 1935 2Sheets-Sheet 2 Patented ay 6, 1947 Iren s TES (Granted under the act ofMarch 3, 1883, as amended April 30, 192.8; 370 0. G. '757) Claims.

This invention relates to a fuse for an aerial bomb and has for oneobject to provide a fuse of the type mentioned having a propeller thatwill be actuated by wind pressure above a bredetermined magnitude to armthe fuse but to unarm the fuse if the wind pressure decreased below thatvalue.

A further object is to provide means to unarm the fuse if the windpressure is directed across the axis of the bomb, as would be the caseif the bomb should catch on a plane after having been released from thebomb rack and so hang with the axis of the bomb transverse to thefore-andaft line of the plane.

In the drawings:

Fig. 1 is a longitudinal section of my invention assembled in the noseof a bomb;

Figs. 2 and 3 are transverse sections on lines iand respectively, ofFig. 1;

Fig. 4 is a schematic detail view of the varies in the safe and in thearmed positions.

Fig. 5 is a detail view of the propeller vane assembly;

Figs. 6 to i0 are taken on line -e of Fig. l, looking down, and show,respectively: Fig. G, the positions of several members when the bomb isunarmed; Fig. '7, when the parts have moved approximately half way tothe armed position; Fig. 8, the armed position; Fig. 9, when movedsubstantially half way to the unarmed position; and Fig. 10, the unarmedposition.

The frame E. of my fuse mechanism is mounted in the body t of the bombthat containsl the main explosive charge, a booster charge 'l surroundedby part of the main charge, and an ex'- plosive lead 3 extending fromthe booster charge to a location where it may be red by the detonator.Detonator holder is rotatably mounted in frame E and is retained thereinby a stud it that extends into a groove H in the detonator holder. Gearhousing member l2 is rotatable in the upper part of frame 5 wherein itis held a pin i3 that is engaged with groove lil and is adapted to beshea-red when the nose of the bomb impacts upon a target, to permit thering pin l5 carried by member l2 to be driven against detonator It inits holder il, the deto-nator at that time being aligned with explosivelead 8.

internal gear Il is carried on a spindle it that is rotatable in memberl2 and that has an eccentric pin i9 extending into a slot 2li indetonator holder lock 2l. This lock has laterally extending flanges 22that ride in rabbets 23 formed in the sides of a cut-away portion inmember l2 and a tab 2d that engages a slot in the .member 35 betweenvanes /l and lll.

Wall of frame 5 to lock members 9 and l2 against rotation with respectto it. The under side of the outer end of lock 2l is cut away asindicated at 2t' to clear lug 26 on member 9 when the lock is retracted,4there being a slot 26' cut into lug 25 to receive the outer end of look2l. A loop t5 depends from the bottom of member l2 and passes undermember 2 l.

Secured to upper end of member l2 is a cupshaped cap 2 carrying aninternal gear V2t that has a greater number of teeth than gear Il. Adouble pinion 29 has one set of teeth 35 to engage gear 28 and anotherset to mesh with gear l1; pinion ZS slides over the surface of disk 3lof gear il' and is rotatable on a pintle 32 eccentrically connected to ashaft t3 by crank 34, shaft 33 being journaled in capEl.

A substantially T-shaped bearing member 35 has its stem'secured to shaft33 and has rotatable shafts 35 and 3'! retained in its `cross piece byscrews 32?; with a spring 39 secured at one end to each of shafts 35 and31 and the other end of each spring attached to member S5 under tensionthat tends to hold the propeller varies 49 and il in the positions shownin Fig. 1, which are the same as the full line positions in Fig. 4. Theradially inner edge of each of vanes lili and il moves in a cut-awayportion of the end of the cross piece of member E5 between shoulders l2and which shoulders serve as stops to limit the rotative movement of thevane with its shaft. Rotation `oi. shaft 33 before dropping the bomb isnormally prevented by a pin dit that passes through the shaft and aportion of cap 2l in which the shaft Yis journaled, the arming wire 45connected to pin it being secured to the bombing rack to withdraw pinIl@ when the bomb is released from the rack.

In Fig. 5 .is shown a `propeller vane assembly having concave-convexvanes at connected to The shape of these vanes it issuch that windpressurevacting transversely of the axis of the bomb body, regardless ofdirection, wl always tend to turn shaft 33 to move the fuse elementsinto the unarmed position, as will be presently explained.

The pitch of vanes #it and Gl is in such a sense that when in theposition shown in Fig. 1, that is, the safe position or" lFig. e, wind`pressure acting on the vanes in the direction of the longitudinal axisof the bomb will keep the fuse elements in the relative positionsdisclosed in Fig. l with the detonator It out of line with the rng pinl5 and the explosive lead 8. It will be noted further that the body ofthe detonator holder 9 is interposed between the firing pin and the lead8, that lug 2B on the detonator holder bears against the lower face ofmember I2 and that the loop 25 on member I2 contacts the detonatorholder 9, thus preventing any motion of member I2 toward detonatorholder 9 and eliminating the possibility of firing pin I5 reaching lead8.

When the vanes d() and il are subjected to wind pressure of suiicientmagnitude, they turn their shafts 36 and 31 against the constraint ofsprings 39 and move to the armed position of Fig. 4. It is apparent thatin this position the torque exerted on shaft 33 is in the oppositeangular sense to the couple developed by the vanes in the safe position.

When the vanes are in the armed position and safety pin I4 has beenwithdrawn, shaft 33 will be driven in the clockwise sense and will,through cra-nk 36 and pin 32, slide pinion 29 around bodily in the samesense. However, due to the engagement of the teeth 39 on the pinion withinternal gear 29, the pinion will be rotated in the counter-clockwisesense due to the fact that the gear 28 is locked to frame 5 by lock 2l.Internal gear I'I will be driven in the same sense as pinion 29 by theteeth 3| on pinion 29 since the number of teeth in gear I'I is less thanthe number in gear 28. For example, if there are two teeth fewer in theformer than in the latter, gear I'I will be rotated only the angulardistance between two teeth of gear II each time shaft 33 makes arevolution, which delays the arming of the fuse. Continued rotation ofgear I'I and of spindle I8 connected thereto will cause eccentric pin I9to withdraw lock 2I from the recess in frame 5 and abut the rear end ofthe lock against the closed end of the cut-away portion in member I2 inwhich the lock slides and thus locks the parts together so that pinion29, member I2 and detonator holder 9 rotate as a unit with shaft 33 andvanes 40 and 4I. In this position the spring detent 48 in member I2 willengage depression 69 in lock 2l and thus form a connection betweenmember I2 and lock 2l to return the mechanism to the locked positionwhen the fuse is being unarmed, as will be hereinafter described.

After lock 2! has been drawn back it clears the lug 26 on detonatorholder 9 and permits member I2 to rotate independently of the detonatorholder, which continues until firing pin I5 is positioned abovedetonator I9 and lug 50 on member I2 engages the lug 29 (Fig. 7), whenthe detonator holder 9 is constrained to rotate with member I2 until lug26 contacts stop 5I fixed to fuse body 5. This prevents further rotationof the parts and stops the mechanism with the detonator I6 aligned withlead 8 and firing pin I5 (Fig. 8). In this position, lug 26 can moveinto cut-out portion 52 in member I2, loop 25 on member I2 can pass intothe cut-out portion 53 in detonator holder 9 and recess 5l! in detcnatorholder 9 is aligned with lug 59 to permit lug 59 to be moved downwardly.With the parts in these positions, upon impact of the nose of the bomb,the member I2 will shear pin I3 and ring pin I5 will be driven intodetonator I 5 to explode the charge of the bomb.

If safety pin 44 is removed while the bomb is on an aircraft in flight,the wind caused by the high speed of the craft would arm the fuse, inwhich condition it would be very dangerous for the craft to land. Thepresent invention prevents such a contingency by causing the fuse tounarm at the slower speeds of landing. When the craft slows downpreparatory to landing, the wind pressure on vanes 49 and 4I becomesinsufficient to hold shafts 36 and 31 turned to the arming positionagainst the tension of springs 39 and the vanes are moved to the safeposition. The wind then drives the vanes to turn shaft 33 in thecounterclockwise sense which moves pinion 29 bodily in the same sensebut the rotation of the pinion on pin 32 is in the opposite sense. Therotation of gear I'I is in the same direction as that of pinion 29 andtherefore spindle I8 and eccentric pin I9 will be made to turn in thesame direction and thus, through lock ZI, member I2 is given a clockwiserotation, longitudinal movement of locking member ZI being prevented byengagement of plunger 48 in depresson 99. Movement of member I2 bringslug 59 on member I2 against lug 55 on the detonator holder 9 (lug 59 isshown approaching lug 55, Fig. 9) and the detonator holder then turnswith member I2 until lug 55 contacts stop 5! (Fig. 10), which preventsfurther movement of the members 9 and I 2. The detonator I6 has now beenturned out of line with lead 8 and detonator holder 9 is interposedbetween firing pin I5 and lead 8. After members 9 and I2 have ceased toturn, shaft I8 rotates until eccentric pin I9 has slid lock 2l out intothe locking position, the contact of lug 55 against stop 5I providingthe necessary reaction to cause plunger 48 to be disengaged fromdepression 49; all parts are then locked and movement of the parts isstopped.

It is to be understood that the above description and accompanyingdrawings comprehend only the general and preferred embodiments of myinvention and that various changes may be made therein within the scopeof the appended claims without sacrificing any of the advantages of thisinvention.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposesWithout the payment of any royalties thereon or therefor.

I claim:

l. In a fuse, a body member having a transverse partition therein, therebeing a hole through said partition, a detonator holder rotatablymounted at one side of said partition, said holder having a recessopening on the side thereof opposite said partition and a holetherethrough adapted to be brought into registry with the hole in saidpartition, a lug on said holder adjacent the hole therein having a slotin its free end, a member slidably and rotatably mounted in said body,shearable means normally acting to prevent sliding movement of saidmember, a lug extending from said member toward said detonator holder toengage said lug on the holder to move said holder to align the holetherein with the hole in said partition, a firing pin positioned on saidmember to be aligned with both said holes when said holes are aligned, afixed lug on said body to engage said lug on the holder and stop theholder when said holes are aligned as aforesaid, a second lug on saidholder engageable with the lug on said member to move said holder to theposition in which said holes are not aligned, a locking element slidablymounted in said member to engage said slotted lug and said body in onerelaative position of these parts and having a transverse slot thereinand a depression in its outer surface, a loop depending from said memberand passing under said element to contact said detonator holder exceptwhen disposed over the recess in said holder, a spring pressed plunger`in said member adapted to engage said depression when said element isin the unlocked position, a shaft journaled in said member, aneccentricpin projecting from said shaft into the slot in said element, a firstinternal gear having a disk body mounted on said shaft, a secondinternal gear having a slightly greater number of teeth than the firstinternal gear connected to said member and disposed adjacent said firstinternal gear,

a pinion disposed to be slidable on the body of said first internal gearand having two sets of `gear teeth each of which sets of teeth isengaged `with one of said internal gears, a shaft rotatably `mounted insaid second internal gear, a crank including a crank arm and a pinjournaled in said pinion and connected by the crank `arm to the lastmentioned shaft, a T-shaped member `having the stem thereof fixed to thelast mentioned shaft, a vane shaft journaled in each end of the head ofsaid T member, a propeller vane `secured to the outer end of each ofsaid vane shafts, said head having stops to limit the rotation of saidvane shafts and resilient means normally holding said vanes directedoutwardly from a bomb by which said fuse is carried.

2. In a fuse, a body member having in it a passage to contain anexplosive lead to an explosive charge, a detonator holder rotatablymounted in said body and having in it a passage to receive a `detonatoradapted to be moved into alignment with the passage in said body whensaid fuse is armed, a member rotatably and slidably mounted in saidbody, means to prevent sliding movement of said member except when inthe armed position, a firing pin carried by said member adapted to bemoved into alignment With said detonator and said lead in the armedposition, a lug on said member extending toward said holder, a firstlugon said holder engageable by the lug on said member to move saidholder into the armed position and a second lug onsaid holder engage--able by the lug on said member to move said holder to the unarmedposition, a fixed lug to stop movement of said holder when in either thefully armed or fully unarmed position, slidabie locking means to locksaid holder and said member to said body in the fully unarmed position,a first internal gear rcarried by said member, a second internal gearhaving a slightly smaller number of teeth than said first gear disposedadjacent thereto, means connected to said second gear to slide saidlocking means and to rotate said member, a bodily movable pinion having-tWo sets of gear teeth whereof one is meshed With each of said internalgears, rotatable shaft carried by said first gear, eccentric meansconnecting said shaft with said pinion, journal means connected to saidshaft, vane shafts rotatably mounted in said journal means, a propellervane mounted on each of said vane shafts, stops on said journal means tolimit the rotation of said vane shafts and resilient means acting uponsaid vane shafts to hold said vanes normally in one position.

3. In a fuse, elements including a firing pin movable to and from thearmed and unarmed positions, a first internal gear operatively connectedto said elements, a second internal gear disposed adjacent thereto, saidsecond gear having a slightly greater number of teeth than said rstgear, a bodily movable pinion having a separate set of gear teeth meshedwith each of said gears, a pin rotatable in said pinion, a rotatableshaft, a crank connecting said pin and said shaft,

a T-shaped member having its stem xed on said shaft, two vane shaftsrotatably mounted in the head of said member, a propeller vane on eachof said vane shafts, a spring connected to each of said shafts normallyto hold said vanes in such position that they Will tend to move saidelements to the unarmed position but adapted to yield at Wind pressuresabove a predetermined minimum to permit the direction of pitch of saidvanes to change to move said elements to the armed position and stopscarried by the head of said member to limit the rotation of said vaneshafts.

4.. In a fuse, elements including a firing pin movable to and from thearmed and unarmed positions, a first internal gear operatively connectedto said elements, a second internal gear disposed adjacent thereto, saidsecond gear having a slightly greater number of teeth than said firstgear, a bodily movable pinion having a separate set of gear teeth meshedwith each of said gears, a pin rotatable in said pinion, a rotatableshaft, a crank connecting said pin and said shaft, a T-shaped memberhaving its stem fixed on said shaft, two vane shafts rotatably mountedin the head of said member, a propeller vane on each of said vaneshafts, a spring connected to each of said shafts normally to hold saidvanes in such position that they Will tend to move said elements to theunarmed position but adapted to yield at Wind pressures above apredetermined minimum to permit the direction of pitch of said vanes tochange to move said elements to the armed position, Stops carried by thehead of said member to limit the rotation of said vane shafts and meansto lock all of said elements together to move as a unit from or towardthe unarmed position and to lock said elements against movement when inthe unarmed position.

5. In a fuse, elements including a firing pin movable to and from thearmed and unarmed positions, a first internal gear operatively connectedto said elements, a second internal gear disposed adjacent thereto, saidsecond gear having a slightly greater number of teeth than said firstgear, a bodilf,T movable pinion having a separate set of gear teeth'me-shed with each of said gears, a pin rotatable in said pinion, arotatable shaft, a crank connecting said pin and said shaft, a T-shapedmember having its stem fixed on said shaft, two vane shafts rotatablymounted in the head of said member, a propeller vane on each of saidvane shafts, a spring connected to each of said shafts normally to holdsaid va-nes in such position that they will tend to move said elementsto the unarmed position but adapted to yield at wind pressures above apredetermined minimum to permit the direction of pitch of said vanes tochange to move said elements to the armed position, stops carried by thehead of said member to limit the rotation of said vane shafts, means tolock all of said elements together to move as a unit from or toward theunarmed position and to lock said elements against movement in theunarmedposition and concave vanes mounted on said member on oppositesides thereof oriented to move said elements always 'toward the unarmedposition when acted upon by Wind ressure transversely to the axis of abomb by which the fuse is carried.

6. In a fuse, elements including a Vfiring pin movable -to and from thearmed andA unarmed positions, a first internal gear operativelyconnected to said elements, a second internal gear disposed adjacentthereto, said second gear having a slightly greater number of teeth thansaid rst gear, a bodily movable pinion having a separate set of gearteeth meshed with each of said gears, a pin rotatable in said pinion, arotatable shaft, a crank connecting said pin and said shaft, a T-shapedmember having its stem xed on said shaft, two vane shafts rotatablymounted in the head of said member, a propeller vane on each of saidvane shafts, a spring connected to each of said shafts normally to holdsaid vanes in such position that they will tend to move said elements tothe unarmed position but adapted to yield at wind pressures above apredeermined minimum to permit the direction of pitch of said vanes tochange to move said elements to the armed position, stops carried by thehead of said member to limit the rotation of said vane shafts andconcave vanes mounted on said member on opposite sides thereof orientedto move said ele ments always toward the unarmed position when actedupon by wind pressure transversely to the axis of a bomb by which thefuse is carried.

'7. In a fuse, elements movable to and from the armed and unarmedpositions and means so to move said elements including propeller vanesadapted to be set with their direction of pitch such that wind pressurebelow a predetermined value on said vanes tends to move said elements tothe unarmed position and to change said direc tion of pitch to tend tomove said elements to the armed position when said pressure is abovesaid predetermined value and resilient means tending to move said vanesto the rst mentioned direction of pitch.

8. In a fuse, elements movable to and from the armed and unarmedpositions, means so to move said elements including propeller vanesadapted to be set with their direction of pitch such that wind pressurebelow a predetermined value on said vanes tends to move said elements tothe un armed position and to change said direction of pitch to tend tomove said elements to the armed position when said pressure is abovesaid predetermined value, means tending to move said vanes to the firstmentioned direction of pitch andvother vanes associated with theaforesaid vanes adapted always to move said elements to the unarmedposition when acted upon by wind pressure transversely to the axis ci abomb by which the fuse is carried.

9. In a fuse, elements movable to and from the armed and unarmedpositions, means including differentially acting gears to move saidelements to delay the movement of said elements, a rotatable shaftoperatively connected to said gears, a T-shaped member having its stemfixed on said shaft, two vane shafts rotatably mounted in the head ofsaid member, a propeller vane on each oi said vane shafts, a springconnected to each of said shafts normally to hold said vanes in suchposition that they will tend to move said elements to the unarmedposition but adapted to yield at wind pressures above a predeterminedminimum to permit the direction of pitch of said vanes to change to movesaid elements to the unarmed position and stops carried by the head ofsaid member to limit the rotation of said Vane shafts.

10. In a fuse, elements movable to and from the armed and unarmedpositions, means so to move said elements including differentiallyacting gears operatively connected to said elements, a rotatable shaftconnected to said gears, propeller vanes connected to said shaft, saidvanes normally having a direction of pitch that will cause said vanes tomove said elements to the unarmed position but movable to a direction ofpitch that will cause said vanes to move said elements to the armedposition and means tending to hold said vanes with the rst mentioneddirection of pitch.

11. In a fuse, elements movable to and from the armed and unarmedpositions, means actuatable by wind pressure to move said elementstoward the unarmed position when said pressure is below a, predeterminedvalue and toward the armed position when said pressure is greater thansaid value and other means tending always to move said elements towardthe unarmed position when acted upon by wind pressure transversely tothe axis of a bomb by which the fuse is carried.

12. In a fuse, a propeller having elements adapted to have a pitchdirection to unarm the fuse when acted upon by wind pressures below apredetermined value and to move to a pitch direction to arm said fusewhen said pressures are greater than said Value and other elementstending always to unarm said fuse when acted upon by wind pressurestransversely to the axis of a bomb by which the fuse is carried.

13. In a fuse, a propeller having elements adapted to have a pitchdirection to unarm the fuse when acted upon by wind pressures below apredetermined value and to move to a pitch direction to arm said fusewhen said pressures are greater than the said value.

14. In a fuse, a propeller having elements adapted to have a pitchdirection to unarm the fuse when acted upon by wind pressures below apredetermined value and to move to a pitch direction to arm said fusewhen said pressures are greater than the said value, other elementstending always to unarm said fuse when acted upon by wind pressurestransversely to the axis of a bomb by which the fuse is carried andmeans actuated by said propeller to delay the arming or unarming of saidfuse.

15. In mechanism for arming and unarming a bomb fuse, a propelleroperatively connected to actuate the mechanism, said propeller includingblades mounted for limited rotation about an edge of each, means biasingsaid blades to one position wherein air pressure of less than apredetermined magnitude thereon actuates the mechanism to the unarmedposition but blades are moved in opposition to the biasing means to thearmed position by air pressure above said magnitude, and curved bladestending always to move said mechanism to the unarmed position when actedupon by air pressures across the aXis of the propeller.

PI-IILIAS H. GIROUARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name

